Appropriate psychophysical procedures are used to measure the various visual functions of patients in the Eye Clinic, particularly thresholds of visibility for the retinal rods and cones and for discrimination of colors, all under standard conditions. These tests are done for the purpose of discovering and monitoring any changes in visual efficiency due to degenerative diseases or toxic medications. Efforts continue in attempts to find or devise test procedures which are more effective, more objective, and less demanding on the patients. Tests were conducted on 377 patients during the past year.